MEMS (Micro Electro Mechanical Systems) is a minimized integrated system which adopts an integrated circuit manufacture technology and a micro-process technology to manufacture a microstructure, a micro-sensor, a micro-actuator, a control and process circuit, and even an interface and a power source on one or multiple chip. Compared to conventional infrared detector, the infrared detector manufactured by using a MEMS technology possesses significant advantages at aspects such as the volume, power consumption, weight, and cost. At present, the infrared detector manufactured by using a MEMS technology is extensively applied to military fair and civil field. According to a difference of working principle, the infrared detector mainly includes a thermo-electric pile detector, a pyroelectricity detector and a thermo-sensitive resistance detector. The thermo-electric pile detector takes advantage of Seebeck effect to transfer a temperature variation caused by an infrared radiation into a voltage signal output. The pyroelectricity infrared detector takes advantage of charge accumulation in a heated body to detect a temperature variation caused by an infrared radiation. The thermo-sensitive resistance infrared detector takes advantage of reading a resistance value to detect a temperature variation caused by an infrared radiation. At present, MEMS infrared detector generally adopts a single-layer suspension microstructure, the technology is simple. However, when a size of the infrared detector chip is reduced, the suspension absorbing region (a film-like absorb layer) servings for absorbing the infrared radiation is reduced at the same time, thus the infrared response rate is reduced greatly.